1. Field of the Invention
The invention generally relates to an article comprising a thermoplastic material. More specifically, the invention relates to a frictional weld joint used to join two body portions of the article.
2. Description of the Related Art
The use of frictional weld joints for coupling together first and second body portions of an article is known in the art. A typically frictional weld joint comprises a first bead extending from the first body portion and a second bead extending from the second body portion. Each of the first and second beads of the typically frictional weld joint has a contact surface. The contact surfaces of the first and second beads are placed into contact with each other and a force is applied to the first body portion to generate friction at the contact surface of the first and second beads. The first and second beads are made from a thermoplastic material and the friction results in an increased temperature of the thermoplastic material. As a result of the increased temperature of the thermoplastic material, the first and second beads nest with one another. Subsequently, the force is removed from the first body portion for allowing the thermoplastic material to cool, which results in the first and second beads fusing together.
The typically frictional weld joint must be capable of resisting stresses, such as bending, tensile, and compressive loads, that act on the typical frictional weld joint without failure. In the case where the article is an air intake manifolds of an internal combustion engine, the stresses acting on the typical frictional weld joint is the result of pressure that builds up within a hollow interior of the air intake manifold. There is a desire in industry to increase the pressure within the hollow interior of the air intake manifold while still utilizing a friction weld joint. There are also industry limitation for the size of the air intake manifold and the frictional weld joint itself. As such, there remains a need to provide an improved frictional weld joint that meets the demands to resist failure when exposed to increases pressures while still meeting industry limitations for size.